We anticipate crystallizing DtxR and IdeR in complex with different oligonucleotides and hope to test these crystals at the SSRL synchrotron. So far, we have been able to obtain crystals of DtxR in complex with a 21mer oligonucleotide that diffract to about 6 E resolution at the SSRL beam lines. It is anticipated that higher resolution will allow the design of novel compounds that cause stronger DNA-binding of the repressor to DNA. The ultimate goal of our studies is the design of novel drugs against M. tuberculosis.